Ferrari Director of Engineering Pat Fry confirmed that the Formula One team will upgrade its car during the final Bahrain test this week.
Although the Maranello team was satisfied with how last week testing sessions at the same circuit progressed from a reliability perspective, Fry added that its main pre-season upgrade was still to come.
"We had a few bits to test correlation and things like that [last week] and then the main upgrade will come through the various stages of the final test," Fry told ESPN.
James Allison, the team's Technical Director added that the team had to iron out several problems during last week's test at Sakhir before they could start experimenting with race setups.
"We worked on learning how to get the best from the 2014 clutch and on tuning the new brake-by-wire system," Allison is quoted by the official Ferrari website.
"We looked in detail at balancing the temperature of all the cooling fluids, a key part of this year's rules, and we began gradually expanding the operating window of the new Energy Recovery System.
"We have been able to start to open up our understanding of the handling characteristics of the car and to begin to learn what sort of setup parameters the tyres respond to. Continuing with this work will be an important part of the programme over the last four days here in Bahrain."